210 CYPEEACEAE (SEDGE FAMILY) 



Pistillate spikes 5-S mm. thick . . (66) C. aquatili*. v. elatutr. 



Scales cuspidate (66) C. aqnatilig, v. cunpidata. 



Scales hidden by the perigynia . . . (66) C. aquatilit, v. virescens. 

 I. Culms low ; leaves mostly basal, smooth ; basal off- 

 shoots chiefly repent 67. C. rigida. 



H. Perigynia elongate, with an empty twisted tip .68. C. torta. 



6. Perigynia nerved. 



Caespitose, not stoloniferous ; green central portion 



of the scale about as broad as the darker margins . 69. C. lenticulari*. 

 Stoloniferous ; preen midrib of the purple or blackish 



scale very slender 70. C. Goodenowii. 



F. Culms numerous in stools ; lower sheaths flbrillose. 



Perigynia elliptic, tapering about equally to base and apex. 

 Pistillate spikes dense, mostly full at base ; scales blunt, 

 slightly if at all exceeding the perigynia. 



Pistillate spikes 2-7 cm. long 71. C. flricta. 



Pistillate spikes 0.5-1.5 cm. long .... (71) C. ttricia, v. eurtitsima. 

 Pistillate spikes rather loose, long-attenuate at base ; 



scales acutish (71) <?. stricta, v. anguxtatn. 



Perigynia obovate or orbicular, shorter than the attenuate 



scales (71) C. gtricta, v. decora. 



E. Perigynia plump, subterete. 



Mature perigynia fleshy, pyriform or subglobose, orange or 



brownish, glabrous 72. C. auna. 



Mature perigynia not fleshy, ellipsoid, slender-stipitate, 



white, pulverulent 78. C. bicolor. 



B. Perigynia lustrous. 

 Perigynia nerved. 



Leaves flat ; bracts ascending 180. C. Grahami. 



Leaves soon involute ; bracts divergent 181. C. rotundata. 



Perigynia nerveless. 



Leaves flat; pistillate spikes subglobose or short-cylindric, 



5-8 mm. thick 179. C. sasralilis. 



Leaves involute or filiform ; pistillate spikes slender, 8-7 mm. 



thick (179) C. saxaUlis, v. miliari*. 



A. Achenes trigonous ; stigmas 3 (very rarely and exceptionally 2) K. 



K. SPIKES SOLITARY, TERMINAL L. 



L. Spikes naked or without large leafy bracts If. 



M. Leaves tongue-shaped, 24 cm. broad 77. C. Frateri. 



M. Leaves grass-like, narrow N. 



N. Spikes monoecious, green or straw-color; perigynia gla- 

 brous O. 

 O. Spikes staminate at tip, few-flowered ; perigynia with entire 



tips. 



Perigynia appressed-ascending, in a linear-cylindrlc 



spike, beakless. 

 Perigynia 2.5-3.5 mm. long; achenes lustrous, not 



puncticnlate, obtusely trigonous .... 75. C. Itptalea. 

 Perigynia 4-5 mm. long ; achenes puncticulate, barely 



lustrous, sharply trigonous 76. C. ffarperi. 



Perigynia soon refracted, slender-beaked . . .74. C. pauciflora. 

 O. Spikes staminate at base, many-flowered ; perigynia with 



long bidentate beaks. 

 Scales of pistillate flowers subulate-tipped . . . 161. C. squarroa. 



Scales blunt 162. C. typhinoid**. 



JT. Spikes dioecious, purplish-brown ; perigynia pubescent. 



Culms shorter than the leaves ; scales' short-aristate, ex- 

 ceeding the perigynia 116. C. pieta. 



Culms exceeding the leaves; scales blunt, shorter than 



the perigynia 92. C. scirpoidea. 



L. Spikes subtended by long leafy bracts. 

 Perigynia somewhat 2-edged. 



Scales all bracteate, overtopping the perigynia . . 89. C. Baetii. 



Only the lowest scales overtopping the perigynia . 90. C. Willdenoioii. 



Perigynia globosa, with slender cylindric beak . . .91. C. Jametii. 

 K. SPIKES 2 OR MORE P. 



P. Perigynia not rigidly bitltntate, the orifice entire or emar- 



ginalt, the teeth if prextnt soft and thin Q. 

 Q. Terminal spike bearing some pistillate flowers R. 

 R. Terminal spike pistillate throughout, brown or purplish, the 



lower spike much smaller; perigynia hairy . . . 92. C. tcirpoidw. 

 R. Terminal spike with both staminate and pistillate flowers S. 

 8. Terminal spike pistillate only at base ; the capillary pedun- 

 cles often basal : perigynia sharply angled . " . . 118. C. pedunculate. 

 8. Terminal spike pistillate at'summit, of, if pistillate at base, 



the spikes mostly near the tip of the culm T. 

 T. Perigvnia ascending U. 



U. Scales brown to purplish-black ; spikes globose, ovoid 

 or thlck-cylindric V. 



